Battery systems of the type mentioned at the outset and batteries and motor vehicles comprising such battery systems are known. The battery systems or the batteries comprising battery systems are used, for example, in motor vehicles with an electric drive, as are used, for example, in hybrid technology or in vehicles driven purely by an electric motor. The battery system can in this case be provided as the only energy source or as a supporting energy source for the motor vehicle drive. In order to drive a vehicle, it may be necessary for the battery system to be a high-voltage/high-current battery system which produces electrical energy for the drive of the motor vehicle, wherein the electric drive energy has high voltages, for example of 800 V, and/or high currents, for example of 250 A.
In order to be able to ensure safe operation of the battery system, the determination unit is provided. This determines the battery current output by the battery system during operation and measured by the measurement unit and can indicate a fault case, for example in the case of impermissible battery currents.
For example, EP 1 411 364 B1 discloses a battery comprising a determination unit formed separately from the battery, with which determination unit a battery current output by the battery is monitored during operation. DE 10 2004 049 153 A1 discloses a conductor section which can be connected to a battery and which is formed with a measurement section. Battery currents flowing through this measurement section can be determined by a determination unit which can be connected to the measurement section. The determination units described in these documents are formed as separate units for connection to battery contacts of the battery. As a result, the known determination units require a certain amount of installation space outside the battery. However, installation space is very limited, in particular in the case of an automotive application. Furthermore, the known external determination units can only measure battery currents output by the battery. Internal battery currents cannot be determined.
Although the known apparatuses contribute to the operational safety of the battery system since they can identify impermissible high battery currents, it may arise that, owing to the type of connection used for the determination units, these determination units are susceptible to electromagnetic interference. As the distance from the at least one battery cell increases, the line length between the respective determination unit and the battery cell also increases, as a result of which it is more probable that electromagnetic interference influencing the battery current measurement is coupled into an impermissible degree for the determination unit. As a result, the operational safety of the battery system, the battery and/or the motor vehicle can be reduced.